US2298823A - Thermostatic switch - Google Patents

Description

Oct. 13, 1942. s CRUM 2,298,823

` THRMGE''ATIC SWITCH Filed oct. 15, 1959 lll/[1111111414111 1111/11//1//11/1/11lll/111111111 5 6 numtor Stephen @ummm .IFI gogh 3936 E as /fLQ-vx MM i i attorney li Patented Oct. 13, 1942 THERMOSTATIC SWITCH Stephen Crum, Minneapolis, Minn., assigner to Minneapolis-Honeywell Regulator Company,

Minneapolis, Minn., a corporation of Delaware Application October 13, 1939, Serial No. 299,315

21 Claims.

This invention is directed generally to thermostatic switches, and more particularly to that type of switch which is adapted to respond to the variations in temperature of the surface of a member.

One of ,the objects oi the present invention is to improve the construction of devices of this character so that they may be more easily made and assembled, and so that they may be more easily calibrated and adjusted.

Another object is to mount the thermostat housing outside and on the rear of the main switch casing and to provide it witha pair of mounting arms which are rotatable about said housing through 360 degrees. Thus the device may be vertically mounted on a pipe or other surface regardless of whether it is horizontal, vertical, or any position in between.

Another object is to provide a simple and novel means of adjusting the control setting of the device from outside the casing and to provide a scale on the adjusting arm which can be readily observed.

Still another object of the invention is to have a single resilient member which holds a rotatable carriage for the thermostat and the adjusting arm therefor in operative relation with the casing, and also supplies the frictional force on the adjusting arm to maintain it in its adjusted position. This resilient member relies upon openings in the sides of the casing for holding it in operative position.

These and other objects will readily become apparent as the following specication is read in the light of the accompanying drawing, in

which Figure 1 is a front elevation of the control device with the cover on,

Figure 2 is a side view partially in section, taken along the line 2-2 of Figure 1,

Figure 3 is a section taken along the line 3-3 of Figure 2,

Figure 4 is a detail view of the mounting for one end of the resilient member which holds the parts in assembled relation,

Figure 5 is a plan view of the adjusting arm with an adjustable stop attached, and

Figure 6 is a front elevation of the adjusting arm and stop shown in Figure 5.

Referring now to the drawing it will be seen that the casing I I which is adapted to be mounted in a vertical position supports the various parts which go to make up the control device of the present invention. Suitably connected erally circular in outline. This housing may be provided with a series of extensions I3 (Figure 3) which pass through slots in the casing II and are bent over as shown to securely connect the housing I2 to the rear of the casing II. The casing II is provided with a hole I4 in which is rotatably mounted the sleeve I5. Secured to the sleeve I5 inside of the housing I2 is a supporting arm I6 which carries at its upper end I1 one end' of a coiled bimetallic thermostat I8. The arm I6 seats against a shoulder I9 on the sleeve I5 and is secured to the sleeve by peening over the end of the sleeve.

Seated against an opposite shoulder 2| on the sleeve I5 is a disc 22 which has a circumferential depression 23 adapted` to bear against the rear surface of the casing II. If desired a special bearing member may be placed on the rear of the casing II to cooperate with circumferential depression 23 to provide a bearing surface and obtain a more uniform sliding friction as the disc 22 is rotated.

The sleeve I5 is provided with a reduced end 24 which forms a third shoulder against which a centering washer 26 is adapted to seat. An adjusting arm 21 is provided with a hole which receives the washer 26 as the adjusting arm is mounted over the sleeve I5. Mounted over the reduced portion 24 of the sleeve I5 and engaging the washer 26 and a portion of the adjusting arm 21 is a bearing washer 30. The above enumerated parts are held in assembled relation with respect to each other and with respect to the casing II by means of a resilient member 32 which is provided with a central hole 33 which receives the reduced portion 24 of the sleeve I5. The resilient member 32 is provided with a reduced end 35 which extends through a hole 3I in the right-hand side of the casing II as seen in Figure 3 and a second reduced end 36 which extends through a hole 31 in the other side oi the casing II. Engagement of these ends Within the holes 36 and 31 cause the resilient member to bow in the middle and force the disc 22 agains the rear of the casing I I and also to maintain the washers 26 and 30 as well as the adjusting ar'fn 21 in assembled relation with respect to the slee-ve I5 and casing II.

Referring to the detail view in Figure 4 it i be seen that the hole 31 is provided with a w cned portion 36 adjacent the rear of the cas Il and a reduced part 39 which is just w enough to receive the reduced en. resilient member 32. The widene:

to the rear of the casing Il is a housing I2 gen- 55 provided so that in assembling the de. e n

36 including the shoulders 40 may be inserted through the widened portion 38 as the resilient member 32 is moved to the left as seen in Figure 3 to permit the end 35 to be swung downwardly until itcan be moved into the hole 36 provided for it in the casing II. After the end 35 has been put in position to be inserted into the hole 36, the resilient member is moved to ward the right at which time the hole 33 receives the reduced end 24 of the sleeve I5 and the end 36 of the member 32 is released to permit it to enter the reduced portion 39 of the hole 31. It will'be appreciated that as the holes 3| and 31 are located adjacent the rear of the'casing II that the resilient member 32 is bent so as to exert a force on the sleeve I tending to move it toward the right as seen in FigureV 2. This action forcesV the disc 22 against the casing II thereby producing a friction which resists rotationpi the disc 22.

The ciuter`Y end of the bimetallic helix I8 is carried by the'ed I1 of the arm I6 and the inner end is connected to the actuating rod 42 which extends through the opening in the sleeve I5 and into the casing II. The inner end of the rod 42 carries a member 43 which is adjustably positioned thereon by means of the screw 44. Member 43 supports the switch clip 45 inA which is mounted the mercury switch 46. The wire 41 is used to secure the switch 46 in the proper position in the switch clip 45.

Adjusting arm 21 is provided with arcuate slot 49 through which is passeda screw 56 which enters a tapped hole 5I in an extension 52 on the bearing disc 22. By this arrangement the relative positions of the bearing disc 22 and the adjusting arm 21 may be varied in order to calibrate the control device. The adjusting arm 21 is provided with a horizontal extension 54 and avportion 55 which is spaced from therear of the casing II and which extends downwardly to a point just belowthe axis of the rod 42. The portion 55 of the arm 21 carries a head 56 which has a kerf 51which is adapted to receive the blade of a screw-driver. This head 56 is on the axis of the actuating rod 42 about which the adjusting arm 21 is rotated. Therefore if the head 56 Is rotated byV means of a screw-driver it will not be displaced other than in a rotary sense and the adjusting arm 21 will be rotated about the axis 42.

. A cover 60 is adapted to b e placed about the casing II to completely enclose the mercury switch, the adjusting arm 21 and related parts. The cover 60 is provided with a plurality of indentations 6I which t into holes 62 in thecasing II in order to frictionally maintain the cover :on the casing lI I. The cover 60 is provided with a. hole 63 in its face which receives a portion of the head 56 so that a screw driver may be applied thereto for rotating the adjusting arm 21 while the cover is in place. Directly above the hole 63 is a second hole 65 through which a portion of the adjusting arm may be seen. This portion of the arm may be inscribed with a scale 66 for indicating the adjustment of the control device. The hole 65 may have an indicating pointer 61 forcooperation with the scale and a window of transparent material may close this hole if desired.

A mounting device generally indicated at 'I0 i which is provided with a pair of arms 1I and a central opening 12 having sloping sides 13 is mounted over the thermostat housing I2. Each of the arms is provided with a hole 'I4 by means tached to the arms for mounting the control device on a pipe orother member to whose temperature the thermostat I8 is adapted to re` spond, so that the rear of the housing I2 is held in heat conducting relationship with the surface of the pipe or member. It will be noted that the housing I2 extends slightly beyond the arms 1I so that as the strap connected to the arm 1I is tightened the housing I2 will be drawn into rmer engagement with the surface of the member on which it is being mounted. It will further be ,noted that the member I0 may be rotated about the housing I 2 through 360 so that the device may be mounted in a vertical position regardless of the angular position of the member 10 so long as this member is in a vertical plane. In other words, the device may be mounted with equal facility on a pipe which extends vertically; horizontally or any position in between. A further feature to be notedis that as the strap is drawn tighter the sloping sides 13 of the member 10 grip the sides and the housing I2 more firmly thereby resisting rotation of the casing II with respect to the member 10. Therefore when the control device is once mountedl and the strap tightened it will remain in a vertical position.

With the control device mounted as described above the heat from the member to which it is Ymounted will be conducted through the housing I2 and to the bimetallic element I 8. This will cause the element to expand and the coiling and uncoiling of this element due to expansion and contraction will cause a rotation of the actuating rod 42 and hence anrotation of the mercury switch 46 to make and break\ the circuit therethrough. It will be seen that the bimetallic element I8 is so proportioned with respect to the rod 42 and mercury switch 46 that it will carry these elements entirely by its own resistance so that nor.- mally the actuating rod 42 is free of the sleeve I5 and does not rest upon the sides of the hole 43 through this sleeve.

As set forth above in order to adjust the temperature at which the switch 46 will make and break the circuit, the head 56 is rotated by means of a screw-driver causing thearm 21 to rotate about the actuating rod 42' as a center.y As the arm 21 rotates it carries with it the disc 22 and sleeve I5 which in turn rotates the outer end of the bimetallic coil I8 thereby Varying the position of the mercury switch 46 and hence adjusting the temperature setting of the device. The relative rotation provided between the adjusting arm 21 and the extension 52 of the disc 22 `permits'the proper calibration of the thermostat I8 with respect to the scale 66. It will be noted that the adjusting arm 21 is provided with two angular extensions 16 and that the rotation `of the arm 21 is limited by the engagement of one or the other of these extensions 16 with the resilient member 32.

In some cases it may be desirable to limit the extent to which the device may be adjusted in addition to the limit normally provided by the engagement of one of the extensions 16 with the resilient member 32. In order to provide for this an auxiliary stop member may be mounted concentrically on the head 56 as shown at 8| in Figures 5 and 6. This stop member is provided with a rearwardly extending portion 82 and a generally horizontally extending portion 83 which is provided with a slot 84. r'I'he screw 85 extends through a hole in the portion 54 of the adjusting arm 21 and through the slot 84 in the stop member 80. A nut 86 is screwed on the end of the screw '85 and is adapted to be tightened against the portion 83 of the stop B0 in order to lock the stop 80 and the adjusting arm 21 in any predetermined position. It will be noted that the horizontally extending portion 83 may extend out beyond the angular extension 16 on the adjusting arm 21 vso that as the adjusting arm'21 is rotated in a clockwise direction as viewed in Figures 3 and 6, the extension 83 on the stop member 80 will engage the resilient member 32 thereby limiting the rotation of the arm 21.

' The stop member 80 is provided with a shoulder 81 which cooperates with the scale 86 to indicate the temperature to which the adjustment of the arm 21 has been limited. In other words, if it is desired to limit the temperature to which this device may be adjusted to 200 the member 80 is set by means of the screw 85 and nut 86 until the shoulder 81 points to the 200 mark on the scale 66. When this adjustment has been made the extension 83 will engage the resilient member 32 when the device has been set to 200 thereby preventing any further adjustments to a higher temperature.

vThe usual leveling indicator 90 is provided so that it can readily be determined when the casing II has been mounted in the proper vertical position.

As various changes and modifications of this invention may occurto those who are skilled in the art, it is to be understood that I am to be limited only by the scope of the appended claims and not by the specific embodiment disclosed.

I claim as my invention:

1. In a device of the character described, an assembly comprising a switch casing and a thermostat housing mounted on said casing outside thereof, said housing having a surface adapted to be placed against a body to whose temperature the thermostatis to respond, a thermostat in said housing, a switch in said casing actuated by said thermostat, and means for mounting said assembly so that said surface of the housing is held against said body. said means being movable with respect to said assembly so that the assembly may be properly levelled when it is mounted.

2. In a device of the character described. an assembly comprising a switch casing and a thermostat housing mounted on said casing outside thereof, said housing having a surface adapted to be placed against a body to whose temperature the thermostat is to respond, a thermostat in said housing, a switch in said casing actuated by said thermostat, and mounting means rotatably carried by said housing for holding said surface against said body, said rotatable mounting means facilitating levelling of said assembly as it is being mounted.

3. A device of the character described comprising in combination, a casing having an aperture, a sleeve rotatably mounted in said aperture, a coiled birnetalilc thermostat outside of said casing and connected atvone end to said sleeve, a rod extending through said sleeve and connected to the other end of said thermostat for rotation thereby, a switch within said casing actuated by said rod, a housing for said thermostat attached to and projecting from saidgasing, and means cooperating with said housing foi-supporting said ..device with one surface of said housing against a body to whose temperature the thermostat responds, said means being rotatable with respect to said housing whereby said device may be levelled as it is mounted.

4. A device of the character described comprising in combination, a casing having an aperture, a sleeve rotatably mounted in said aperture, a coiled bimetallic thermostat outside of said casing and connected at one end to said sleeve, a rod extending through said sleeve and connected to the other end of said thermostat for rotation thereby, a switch within said casing actuated by said rod, a housing for said therniostat attached to and projecting from the back of said casing. means cooperating with said housing for supporting said device with the back surface of said housing against a body to whose temperature the thermostat responds, said means being rotatable with respect to said housing whereby said device may be levelled as it is mounted, an arm for rotating said sleeve and hence adjusting the temperature at which said thermostat will actuate said switch, a scale on said arm, means for rotating said arm, a cover for sald casing having aperture means in the front thereof through which a portion of the scale indicative of the adjustment of the thermostatt may be seen, and through access may be had to the means for rotating said adjusting arm.

5. A 'device of the character described comprising in combination, a switch casing, a sleeve extending through an aperture in said casing, a coiled bimetallic thermostat located outside of said casing, one end of said thermostat being positionY by said sleeve, a switch inside of said casing, means controlled by the other end of said thermostat and extending through said sleeve to actuate said switch, an arm for rotating said sleeve and hence adjusting the temperature' at which said thermostat will actuate said switch, a scale on said arm, a cover for said casing, said cover having indicating means including an aperture in the front thereof by means of which that portion of the scale indicative of the adjustment of the thermostat may be seen, and means for rotating said arm, said last named means being in substantial alignment with said sleeve, said cover having a second aperture in the front thereof in alignment with said rotating means for access thereto.

6. A device of the character described comprising in combination, a switch casing, a sleeve extending through an aperture in the rear of said casing, a coiled bimetallic thermostat located outside of said casing, one end of said thermostat being positioned by said sleeve, a switch inside of said casing, means controlled by the other end of said thermostat and extending through said sleeve to actuate said switch, an arm for rotating said sleeve and hence adjusting the temperature at which` said thermostat will actuate said switch, said arm having a portion extending substantially parallel to the rear of said casing, means on the last named portion of said arm in substantial alignmentwith said sleeve for rotating said arm and sleeve, a cover for said casing, and a scale on said parallel portion of said arm, said cover having indicating means including an aperture by means of which that portion of the scale indicative of the adjustment of the thermostat is visible, said cover being provided with a second aperture by means of which accessmay be had to the means for rotating said adjusting arm.

7. A device of the character described comprising in combination, a switch casing, a sleeve extending through an aperture in said casing, a

coiled bimetallio thermostat located outside of said casing, one end of said thermostat being positioned Vby said sleeve, a switch inside of said Casing, means controlled by the other end of said thermostat and extending through said sleeve to actuate said switch,A an arm for rotating said sleeve and hence adjusting the temperature at which said thermostat will actuate said switch, indicia for` indicating the adjustment thereof, said casing being provided with means for limiting the rotation of said arm, adjustable means for varying the extent to which said limiting means will limit the rotation of said arm, and an indicator cooperable with said adjustable means and said indicia for indicating the limit setting.

8. A device of the character described comprising in combination, a switch casing, a sleeve extending through an aperture in said casing, a coiled bimetaliic thermostat located outside of said casing, one end of said thermostat being positioned by said sleeve, a switch inside of said casing, means controlled by the other end of said thermostat and extending through said sleeve to actuate said switch, an arm for rotating said sleeve and hence adjusting the temperature at thermostat and extending through* said sleeve, and switch means actuated by said rod.

12. In a device of the character described, a switch casing, a sleeve rotatably mounted in the rear of said casing, a bearing surface on said cas- Y ing, a bearing member carried by said sleeve.

which said thermostat will actuate said switch,

indicia for indicating the adjustment thereof, said casing being provided with means for limiting the rotation of said arm, adjustable means for varyng the extent to which said limiting means will limit the rotation of said arm, said last mentioned means being adjustably carried by said adjusting arm, and an indicator cooperable with said adjustable means and said indicia for indicating the limit setting.

9. In 'a device ofthe character described, a casing, means rotatably mounted in the rear of said casing, said means having a bearing portion, said casing being provided with a. bearing surface cooperating with said bearing portion, resilient means urging said rotatable means in engagement with said bearing surface, the sides of said casing having holes with which the ends of said resilient means engage, thermostatic means connected at one end to said rotatable means, and' a control `device actuated by the other end of said thermostatic means.

l0. In a device of the character described, a switch casing, a sleeve rotatably mounted in the rear of said casing, a bearing surface on said casing, a bearing member carried by said sleeve, an elongated resilient member` seated over said sleeve and having reduced ends forming shoulders, said reduced ends extending through apertures in opposite sides of the casing, said shoulders abutting said sides, a thermostat mounted at one end on said sleeve, a rod connected to the other end of said thermostat and extending through said sleeve, and switch means actuated by said rod. Y

11. In a device of the character described. a switch casing, ausleeve rotatably mounted in the rear of said casing, a bearing surface on said casing,a bearing member carried by said sleeve an elongated resilient member seated over said sleeve and having reduced ends forming shoulders, said reduced ends extending through apertures in opposite sides of the casing, said shoul- `ders abutting said sides, one of said apertures having a wider portion adapted to receive the shoulders at one end of said resilient member as the other end is being mounted in'its aperture, a thermostat mounted at one end on said sleeve, a rod connected to the other end of said operating said control means supported by said an elongated resilient member seated over said sleeve and having reduced ends forming shoul-` ders, said reduced ends extending through apertures in oppOsite sides of the casing, said shoulders abutting said sides, a thermostat mounted at one end on said sleeve, a rod connected to the other end of said thermostat and extending through said sleeve, switch means actuated by said rod, and means for manually rotating said sleeve whereby the temperature at which the thermostat actuates said switch is'varied.

13.. In a device of the character described, a switch casing, a sleeve rotatably mounted in the rear of said casing, a bearing surface on s'aid casing, a bearing member carried by said sleeve, an elongated resilient member seated over said sleeve and having reduced ends forming shoulders, said reduced ends extending through apertures in opposite sides of the casing, said shoulders abutting said sides, a thermostat mounted at one end on said sleeve, a rod connected to the other end of said thermostat in a manner to be rotated thereby on temperature changes, said rod extending through said sleeve and within said casing, and a mercury switch mounted on the end of said rod within said casing,

14. In a device of the character described, a switch casing, a sleeve rotatably mounted in the rear of said casing, a bearing surface on said casing. a bearing member carried by said sleeve, an elongated resilient member seated over said sleeve and having reduced ends forming shoulders, said reduced ends extending through apertures in opposite sides of the casing, said shoulders abutting said sides, a thermostat mounted at one end on said sleeve, a rod connected to the other end of said thermostat in a manner to be rotated thereby on temperature changes, said rod extending through said sleeve-and within said casing, a mercury switch mounted on the end of said rod within said casing, and means for rotating the sleeve whereby the temperature at which the thermostat actuates the mercury switch is varied.

15. In a device of the character described, control means, a casing therefor, a thermostat for casing so as to project exteriorly thereof, a housing for said thermostat attached to said casing and having a surface adapted to be placed against a body to whose temperature thethermostat responds, said housing being of substantially circular cross-section with an enlarged portion adjacasing so as to project exteriorly thereof, a housing for said thermostat attached to said casing and having a surface adapted to be placedagainst a body to whose temperature the thermostat re- .means of which said surface may be pressed against said body, said pressing action holding said collar in engagement with said tapered portion, thereby resisting relative rotation therebetween.

17. A device of the character described comprising in combination, a switch casing, a sleeve extending through an aperture in said casing, a coiled bimetallic thermostat located outside of said casing, one end of said thermostat being positioned by said sleeve, a switch inside of said casing, means controlled by the other end of said thermostat and extending through said sleeve to actuate said switch, an arm for rotating said sleeve and hence adjusting the temperature at which said thermostat will actuate said switch, a

stationary member in said casing for limiting the rotation of said arm, and a member adjustab y mounted on said arm for engaging said stationary member. said adjustably mounted member serving to vary the limiting position to which said arm may be moved in one direction.

18. In a device of the character described, a casing, thermostatic means mounted at one side of said casing, a switch, means operatively connecting said switch to said thermostatic means, means for supporting said switch and said connecting means, and an elongated resilient member for holding said supporting means against said side of said casing, said elongated member having a central portion adapted to engage said supporting means and reduced end portions forming shoulders, said reduced ends extending through apertures in opposite sides of said casing laterally disposed from said one side, said shoulders abutting said opposite sides, one of said apertures having a wider portion adapted to receive the shoulder at one end of said member as the other end is being mounted in its aperture.

19. In a device of the character described, a switch casing, a sleeve rotatabiy mounted inthe rear of said casing, a bearing surface on said casing, a bearing member carried by said sleeve, an elongated resilient member seated over said sleeve and having reduced ends forming shoulders, said reduced ends extending through apertures in opposite sides of the casing, said shoulders abutting said sides, a thermostat mounted at one end on said sleeve, a rod connected to thev other end of said thermostat and extending through said sleeve, switch means actuated by said rod, an arm for rotating said sleeve whereby the temperature at which said thermostat actuates said switch is varied, and a projection on said arm for engaging said resilient member to limit the rotation of said arm.

20. In a device of the character described, a switch casing, a sleeve rotatably mounted in the rear of said casing, a bearing surface on said casing, a bearing member' carried by said sleeve, an elongated resilient member seated over said sleeve and having reduced ends forming shcul ders, said reduced ends extending through aper* tures in opposite sides of the casing, said shoul ders abutting said sides, a thermostat mounted at one end on said sleeve, a rod connected to the other end of said thermostat and extending through said sleeve, switch means actuated by said rod, an arm for rotating said sleeve whereby the temperature at which said thermostat actuates said switch is varied, and a member adjustably mounted on said arm -ior engaging said resilient member to limit the rotation of said arm.

2l. A device of the character described comprising in combination., a switch casing, a sleeve extending "b ough aperture in said casing, a coiled bime thermostat located outside of said casing, one end of said thermostat being positioned bv said sleeve, a switch inside of said casing, mear controlled by the other end of said thermostat extending through said sleeve to actuatesaid switch, an arm for rotating said sleeve i hence adjusting the temperature at which d thermostat will actuate said switch, stop means on said casing for limiting the rotation oi said arm, adjustable means on said -arm for said stop to vary the limiting position to which said arm may be moved in one direction, and a scale on said arm, said casing having an aperture therein by means of which that portion of the scale indicative of the actuating temperature of the thermostat may be seen, said adjustable means having a portion cooperating with said scale to indicate the limit of said actuating temperature as determined by said adjustable means.

' STEPHEN CRUM.

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